It is located in north County Leitrim near the village of Killarga.

Belhavel Lough is about 2 kilometres (1.2 mi) south of Killarga and 5 km (3.1 mi) north of Drumkeeran.

[2] The lake drains east into the Diffagher River, which eventually reaches Lough Allen.

[1] The water quality was reported to be satisfactory c. 2001 – c. 2003 with a mesotrophic rating,[4][n 1] but had a "poor" ecological status c. 2007 – c. 2009 indicating pollution,[6] though Zebra mussel infestation was not reported.

[7] The ecology of Belhavel Lough, and other county waterways, is threatened by curly waterweed, zebra mussel, and freshwater clam invasive species.